Civil Engineering - Surveying - Discussion

2. 

If h is the difference in level between end points separated by l, then the slope correction is . The second term may be neglected if the value of h in a 20 m distance is less than

[A]. m
[B]. 1 m
[C]. 2 m
[D]. 3 m

Answer: Option D

Explanation:

No answer description available for this question.

Vijay Patel said: (Aug 22, 2013)  
Second term neglect and l = 20.

So h2 = 2L.

h2 = 2*20.

h = 3.3m.

Near equal to 3m.

Namrathasai said: (Jan 23, 2014)  
Would you please explain the calculations! Why are you taken that h2/2l=1?

Aman said: (Feb 5, 2014)  
If we use any value lesser than 3 and not greater than 3, then answer for slope correction either using the complete formula given above or by eliminating the second term, we will get the same answer. Thus it means that the second term can be eliminated the right answer is 3 and distance kept as 20m.

Vivek Chandel said: (May 21, 2014)  
For slopes of 10 percent or less, the correction to be applied to L for a difference d in elevation between tape ends, or for a horizontal offset d between tape ends, may be computed from,

Cs=(h^2)/(2L).

For a slope greater than 10 percent, Cs may be determined from,
Cs={(h^2)/(2L)}+{(h^4)/8(L^3)}.

Nanda said: (Sep 11, 2014)  
@Vijay patel.

h2 = 2*20
h square = 40.
How come h = 3.3?

Rashmi said: (Oct 4, 2014)  
How 3.30?

Ramu said: (Oct 15, 2014)  
Answer is 1

From answer verification, If we substitute 1/2 in second term then it will negligible compared to other.

Siva said: (Oct 23, 2014)  
h2 = 40 root 40 = 6.32.

How can you get 3.3?

Raju said: (Feb 5, 2015)  
h square = 40.

Square root of 40 = 6.32 or 6.33.

How get it 3.3?

Akshay Vashisht said: (Jun 26, 2015)  
Second term is neglected for slope less than 10%.

Slope for given problem for:

C) (2/20)*100 = 10%.
D) (3/20)*100 = 15%.

So for h = 2 m or less it is neglected.

And for h = 3 m it will be taken into account.

Rajesh said: (Jul 3, 2015)  
How it comes 3.3?

Rajesh said: (Jul 3, 2015)  
How it comes 3.3?

Suparna said: (Sep 9, 2015)  
If h2 = 4O. Then h = 6.324.

How it will come 3.3? Please explain.

Chandradeep said: (Oct 22, 2015)  
For slopes greater than 5% the above formula must be adopted otherwise the second part of the formula can be neglected.

Since the first three options are less than or equal to 5% they can neglected as the 3m is greater than 5% the second part of formula must included. Hence the answer is (D) 3m.

Abhilash Jana said: (Oct 30, 2015)  
When distances are measured along the slope, the equivalent horizontal distance may be determined by applying a slope correction.

The vertical slope angle of the length measured must be measured. (Refer to the figure on the other side).

Thus, For gentle slopes, m<20%.
Ch = h^2/2l.

For steep slopes, 20% <= m <= 30%.
Ch = h^2/2l+h^4/8l^3.

For very steep slopes, m>30%.
Ch = l(1-cos0).

Rahul Verman said: (Mar 4, 2016)  
How it will come 3.3?

Kawal Jee V said: (May 18, 2016)  
@Vijay.

How it comes 3.3? Explain your answer.

Deepesh said: (Jul 13, 2016)  
Two things I found in this discussion,

1) For a slope smaller than 10%, Slope correction = h^2/2l, and,
2) For a slope greater than 10%, Slope correction = h^2/2l + h^4/8l^3 should use.

But finally, I did not get the answer 3 or 3.333.

Please anybody explains this answer in detail.

Thanks in advance;).

Rihaan said: (Aug 20, 2016)  
@Vijay.

How, 3.3?

Vinay said: (Aug 26, 2016)  
How come h = 3.3?

Yps said: (Sep 17, 2016)  
The answer is 3 cm, not 3 m.

Mahavicky said: (Sep 21, 2016)  
How h come in the answer?

Imran Hossain said: (Nov 9, 2016)  
** If h is the difference in level between endpoints separated by l, then the slope correction is c=(h^2/2l)+{h^4/8(l^3)}.

** If h is less than 3m in a length often the 20 m, then the quantity h^4/8(l^3) can be neglected. Hence c = h^2/2l.

Source. Dr. B.C. Punmia.

Pravin Pawar said: (Nov 9, 2016)  
For slope greater than 5% closer a closer approximation of corrected slope can be determined by h2/2l + h4/8l3.
Otherwise taken as h2/2l.

In the above example slope taken as 5% of length.
Length = 20 m therefore slope is 1.
Slope = height/length.

We have slope value equal to 1.
Then h2/2l = 1.
Answer is 6.32 m which is more than 3.

Irfan said: (Nov 10, 2016)  
How 3.3? Explain in detail.

Simha said: (Dec 25, 2016)  
Not getting this. Please explain briefly.

Naga Raju Ch said: (Jan 25, 2017)  
h^2/2l = 1.
h^2/2 * 20 = 1,
h^2/40 = 1.
h^2 = 40.

Therefore(h) =6.32 (how will come 3 answer plz explain briefly).

Tamilarasan said: (Jan 30, 2017)  
How 3.3?

Please explain the answer.

Pratap said: (Feb 20, 2017)  
For slope >=20%, the 2nd term can be neglected.
Taking minimum slope as 20%,
Slope = 20%
or, h/d =20%
or, h/20 = 20%
or, h = 20 * 20%
or, h = 4.

Since the value nearer to 4 is 3, so the right answer is 3.

Mayank said: (Apr 6, 2017)  
FOR SLOPE >=20% THEN 2ND TERM NEGLECTED.
Take min slope 20%,
SLOPE h^2/2l = 20%,
h^2/2 * 20 = 20%,
h^2 = 20% * 40,
h^2 = 8.
h approximately 2.83 which is nearly to 3.

Sandeep Dharani said: (Jun 7, 2017)  
How will get 3.3?

Anybody, please explain it.

Sanjay said: (Jun 17, 2017)  
Here all the options are correct as we apply them in the second term because the answer is in 10^-3.

So it is neglected. As we take to consider the highest value always so 3 is the correct answer.

Aadil said: (Jun 21, 2017)  
The second term may safely be neglected for slopes flatter than about 1 in 25. Therefore,

h^2/2l=25%.
H^2/2*20=0.25,
H^2=10,
H=3.16.=3 (approx).

Radhika said: (Jun 30, 2017)  
How will get 3.3?

P.Ayub said: (Jul 1, 2017)  
If the second term is neglected the slope correction falls under <=20%.
So it may be taken as h^2/2l=20%.

h^2/2*20=0.2.
h=2.82<3.
So answer is 3.

Pradeep said: (Jul 11, 2017)  
Please, explain the answer clearly.

Juhi said: (Jul 13, 2017)  
How it come 3.3?

Please explain clearly.

Rathika said: (Jul 18, 2017)  
Here, root 40 = 6.32.
Then how will get h= 3.3?

Vaibhav Rana said: (Aug 6, 2017)  
@All.

Answer is 1
Very simple put tan(3°)=h/20.
You will get the answer.
h=1m.

Venkatesh said: (Sep 29, 2017)  
How? Explain.

Bala said: (Oct 7, 2017)  
In this case, if we neglected 2nd term the correction should be less 20%. So,(h^2/2x20)<20% or 0.2. results h<2.828 m.

Srinivas Reddy said: (Dec 22, 2017)  
h'2 = 20% * 2 * 20.
= 2.826.

Souvik said: (Jan 26, 2018)  
Thanks for the answer.

Aniket said: (Apr 15, 2018)  
In (h^4) / (8l^3), The Value comes out 0.008 (Almost 0%) up to filling of h=2.9. At h=3m the value comes out 0.01.

so, h=3 is the right answer.

Ghalib said: (May 20, 2018)  
For slope less than 1 in 25 so h/l is less than or eqal to1 in 25 so h is q.

Equal to or less than (.8).

Durga said: (Jul 16, 2018)  
How can you get 3? Please explain the solution in detail.

Latha said: (Aug 24, 2018)  
H^2=2*20.
=6.32.

SUBSTITUTE THE VALUE IN THE FORMULA.
6.32^2/2*20+6.32^4/8*(20^3).
0.998+2.492=3.4 (approx).

Tapas Kumar Dinda said: (Mar 9, 2019)  
H^4/8L^3 = 0 or near to 0 which is neglected to measure, when I put h<3 (1/2,1,2), results are below 1mm, which is hard to measurable. So, 3 is correct.

Vin said: (Jun 4, 2019)  
H should be less than 3.

Even if it is substituted in the formula, the second term will get negligible (very small number-even neglecting the term will not affect the answer).

Shiv said: (Jul 16, 2019)  
Correct @Imran.

As we decrease the value of h less than 3, the second term impact becomes negligence so 3 is the answer.

Frlyrvllz said: (Oct 1, 2019)  
The formula (h^2/2L)+(h^4/8L^3) is for slope that ranges from 20%-30%.

If (h^4/8L^3) is to be neglected, h^2/2L is left and if we are going to equate it with 20% the answer would be 2.8~3 and if h^2/2L is to be equated to 30% the answer would be 3.4~3 therefore the answer is 3.

Swathi said: (Dec 13, 2019)  
How will get 3.3?

Amrit Kshetri said: (Dec 31, 2019)  
The question is wrong it should be h2/2l -h4/8l3 instead of h4/8l3.

Nagadhar said: (Jan 9, 2020)  
How will get 3.3?

Sachin said: (Jan 30, 2020)  
ASSUMING L=100m then ,Cs=(400/(2*100))+(8000/(8*100^3)= 2.001m.
Which less than 3m.

Ajaypal Singh Nirala said: (Apr 20, 2020)  
If the value of h is maximum then h^4 value is greater than the other value. So how is possible to this? Value goes nearest to zero right?

Logeshkanna said: (Apr 28, 2020)  
The answer should be A. 1/2m.

With ref of Punmia : the second term in slope correction shall be neglected for slopes flatter than about 1 in 25 (i.e slope should be lesser than 0.04).

The slope is Vertical distance/Horizontal distance.
.
Here Vertical distance is h and the horizondal distance is √((L)^2 - (h)^2).

L = 20 given in the problem. We need to find, for which value of h the slope will be less than 0.04.

Sub h = 0.5, we get slope = 0.025;
Sub h = 1, we get slope = 0.050;
Sub h = 2, we get slope = 0.100;
Sub h = 3, we get slope = 0.150;

Therefore Option A (h=0.5m) is the correct answer.

Fayez Abusafaqa Ps said: (Jun 19, 2020)  
The error can be accepted upto 10%. thus, the second term divided by the correlational factor equal 0.1.

Assuming the first term is x and the second term is y. Then y/x+y=0.1==> x+y/x=10 with y not zero==>1+x/y=9==>y=9. solve it u will get l=3.

Nandhu said: (Aug 24, 2020)  
The second term can be negleted only if the slopes flatter than 1 in 25..
That means 4%.

i.e, 4% of 20m = 0.8(4/5) ie, H shouldn't higher than 0.8m.
So option A is right.

Kartabo Ketema said: (Sep 6, 2020)  
How it will be 3m? Explain it with the formula.

Khagendra said: (Jan 14, 2021)  
For slope (M) up to 20%.
Slope correction(Sc) = h^2/(2l).
Here d = 20m,
M = h/d,
0.2 = h/20.
H = 0.2 * 20 = 4m.
Here the nearest one is 3m.
So 3m is the appropriate answer.

Dev Narayan Yadav said: (Aug 6, 2021)  
l = 20 m.
H2 = 2l,
H2 = 2*20,
H2 = 40.
And;
H = 6.32 or 6.33,
√40 = 6.32.

Mukesh Das said: (Sep 15, 2021)  
How it will be 3m?

Please explain clearly with the completed formula.

Mukesh Das said: (Sep 15, 2021)  
How it will be 3m?

Please explain clearly with the completed formula.

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